Pkgproof

What the pkgproof MCP server does

The pkgproof MCP server verifies npm packages before installation by sending checks to pkgproof.net. It examines advisories, install scripts, typosquat and combosquat names, package scope, and the relationship between a package and its declared repository. The service also reports package provenance-related information where available through its verification response.

Each result has one of four verdicts: safe, caution, block, or does_not_exist. Reasons identify their source and distinguish factual findings from heuristics. The response is available both as agent-readable text and as structured JSON under structuredContent, with the verdict, reasons, and computation time.

How it works

The server exposes one tool, verify_package. Its required name argument accepts scoped and unscoped npm names, such as @scope/thing or left-pad. An optional version limits the check to an exact release; if omitted, the package is checked without selecting one release. ecosystem defaults to npm, which is the only ecosystem supported by the service.

The first verification for a caller each day uses the free Base route and does not need an account or key. After that, the server can pay $0.05 per verification in USDC. If both payment options are configured, Algorand is preferred; otherwise, Base is used. Calls are processed one at a time per payer, so a second verification is not run concurrently for the same payer.

Setup and configuration

The pkgproof MCP server requires Node 22 or newer and does not require a separately hosted process. A standard client configuration runs it with npx -y @pkgproof/mcp:

{
  "mcpServers": {
    "pkgproof": {
      "command": "npx",
      "args": ["-y", "@pkgproof/mcp"]
    }
  }
}

No environment variables are needed for the free daily verification. Paid use can configure PKGPROOF_ALGORAND_PRIVATE_KEY with a base64 Algorand account key or PKGPROOF_BASE_PRIVATE_KEY with a 0x-prefixed EVM private key. The Algorand account needs USDC on Algorand Mainnet and requires initial account funding and asset opt-in. The Base wallet needs USDC on Base. The README recommends a throwaway wallet because keys in ordinary MCP client configuration are stored as plain text and the server has no spend cap.

Claude Code can install the repository's plugin marketplace entry. Claude Desktop can install a prebuilt .mcpb release bundle, which stores wallet keys in the operating system's secret store.

Tools and capabilities

The pkgproof MCP server provides only verify_package. It covers:

• npm advisory checks
• Install-script checks
• Typosquat and combosquat name checks
• Scope and declared-repository checks
• Verdicts with source-labelled facts and heuristics
• Structured output containing the verdict, reasons, and calculation time

The published package is listed in the MCP Registry as net.pkgproof/pkgproof, and releases from version 0.1.1 onward include CI build signatures and npm provenance attestations.

Limitations and notes

This service covers npm only; changing ecosystem does not add support for another package ecosystem. The free allowance is one verification per caller per day, and paid calls cost $0.05 each. Payment routes use different key formats and networks, so an Algorand key cannot be used as a Base key or vice versa. A configured wallet is charged only after the free attempt has been used.

The package verification result is a service assessment rather than a guarantee that software is safe. Heuristic findings are labelled separately from facts, and package checks can return does_not_exist when the requested package is unavailable.